Mobile machines, including on- and off-highway haul and vocational trucks, wheel loaders, motor graders, and other types of heavy machinery often include a mechanical transmission coupled to an engine through a torque converter assembly. A torque converter utilizes a fluid coupling that allows slippage between an engine and a transmission. Torque converters may also utilize one or more clutches, such as an impeller clutch and a lockup clutch, to improve efficiency and increase flexibility of operation of the mobile machine.
One device providing a torque converter with multiple clutches is disclosed in U.S. Pat. No. 5,947,242 to Creger. Creger discloses an electrohydraulic control device for a drive train. Specifically, Creger discloses an engine, a torque converter having an impeller element, a reactor element and a turbine element, and an impeller clutch drivingly connected between the engine and the impeller element. Creger also discloses a set of service brakes. Creger discloses that an impeller brake is drivingly connected between the impeller element and a stationary support member. A controller receives at least one input signal representing an operation of the drive train and responsively controls one of the impeller clutch, impeller brake, and brake set.
Although Creger discloses an impeller clutch and an impeller brake for a hydraulic torque converter, further improvement is possible. For example, Creger does not disclose the manner in which the hydraulic components are physically or fluidly connected to the hydraulic torque converter or to the mobile machine.